Natural butter is made by churning a high butterfat liquid dairy product to destabilize the emulsified butterfat contained therein and coagulate that butterfat as butter. In the more traditional processes for producing butter, the dairy product, e.g., whole milk or cream or mixtures thereof, is first soured with a streptococcus organism, which provides some flavor and facilitates the destabilization of the butterfat emulsified in the dairy product. However, it is not necessary to sour the dairy product prior to churning, and some commercial processes do not do so. Indeed, a number of processes have been proposed in the prior art for producing butter which depart markedly from the traditional butter making process.
As an example of the foregoing, U.S. Pat. No. 2,505,654 recognizes that butter is made by changing cream from a fat-disbursed-in-milk serum state to a milk serum-disbursed-in-fat state, and that this, in general, involves a mechanical conversion of the butterfat from the small discreet globules suspended in the milk serum to a coalesced condition wherein the fat globules are merged into a substantially continuous mass which, upon working out of a predetermined amount of the milk serum, becomes commercial butter. Thus, that patent also recognizes that, at first blush, it would appear that butter could be made from cream by concentrating the fat until it coalesces into a continuous phase. However, also as reported in that patent, this is not true, because one of the important characteristics of butter is its flavor and odor, and both of these qualities are imparted to the finished butter by substances at least partly contained in the milk serum. Thus, the fat can be concentrated only to a certain degree while still retaining sufficient milk serum to insure good flavor and odor in the finished butter. The reference goes on to then propose a continuous process for producing butter, rather than the traditional batch process, based on concentrating the cream, e.g., by centrifugal or gravitational separation, and subjecting the concentrated cream to freezing, whereby milk serum and fat separate to a certain extent. The then concentrated fat is thawed and churned to produce butter in a continuous process.
As part of that process, free milk serum is drained off and the semi-solid continuous phase is extruded as butter, but in that extrusion, the butter is "worked" to adjust the amount of milk serum remaining therein and the texture and consistency of the butter can somewhat be regulated by the amount of milk serum retained in the butter. Accordingly, in this process some ability to control the texture and consistency of the butter is possible, as opposed to the more traditional processes, where the texture and consistency are essentially non-controllable. This feature of that process is in recognition of a long-standing problem in the art in connection with butter.
In this latter regard, as is well known, butter must be refrigerated for storage purposes, since otherwise the butter will rapidly turn rancid and, in addition, will "oil-out" (the butter will partially lose its shape and/or butter oil will separate from the butter). However, at refrigeration temperatures, e.g., 35.degree. to 45.degree. F., the fat of the butter crystalizes and forms a relatively stiff matrix. Since butter, as noted in the aforementioned patent, is a composition where the butterfat forms a continuous matrix, the stiff crystalized butter matrix resists spreading, e.g., spreading the butter on toast with a knife. In other words, ordinary butter at refrigeration temperatures is essentially non-spreadable.
The usual means of avoiding this problem is to remove the butter from refrigeration temperatures and allow the butter to warm prior to use. However, this is an inconvenience, since depending upon the amount and configuration of the butter, e.g., a stick of butter, the time of warming sufficiently to make the butter spreadable can be as long as one-half hour or more. In addition, if the butter is inadvertently left at room temperature or above for a significant period of time, the butter will tend to "oil-out", mainly in that the butter begins to lose its shape. Further, the temperature of the butter when being spread is relatively critical. For example, if the butter has warmed too much, e.g., during a warm summer day, then when the butter is applied to, for example, warm toast, e.g. toast at about 95.degree. F., the butter will immediately melt (oil-out to a considerable degree) onto the areas of application on the toast and be absorbed by the toast, mainly as a liquid or semi-solid, in those localized areas. This prevents a uniform spreading of the butter on the toast and is a result of the butter "oiling-out".
Beyond the ability to somewhat adjust the texture and consistency by substantial departures from the usual commercial butter making process, such as that described by U.S. Pat. No. 2,505,654, as discussed above, the art has sought other means of avoiding the problem of the spreadability of butter, especially at refrigeration temperatures. These efforts in the art may be generally classified as the production of "butter-like" spreads. The most notable of these is margarine, but margarine is based on vegetable fats, rather than butterfat, and for much of the reasons explained in U.S. Pat. No. 2,505,654, and briefly noted above, the taste and odor of margarine are not similar to butter. Thus, while margarine is widely accepted as a spread, it is not considerd to be substantially similar to butter in either taste, texture or mouth feel.
U.S. Pat. No. 4,307,125 discloses a low-fat butterlike product having good low temperature spreadability. This process involves adding an emulsifier and a hydrocolloid to cream, chilling the mixture and causing a phase inversion (reversal) without syneresis (the oil-in-water emulsion of the cream is reversed to a water-in-oil emulsion without substantial separation of the butterfat). In a sense, therefore, this approach makes a "gel" structure, which is necessary since the water content of the cream is substantially retained in the product. Such spreads, therefore, have relatively low butterfat contents and the taste and texture is not similar to butter, although the composition has better spreading properties than natural butter. For example, as that patent points out, some butters will have a needle penetrometer number at 2.degree. C. of about 27, while the low-fat spread of that patent will have a needle penetrometer number at the same temperature of about 149, the penetrometer number being an index of spreadability.
Other approaches in the art have been toward separating the components of the butterfat and reemulsifying certain of those components to achieve a more spreadable butter-like spread. Thus, U.S. Pat. No. 4,436,760 prepares a water-in-oil emulsion based on a low-melting butterfat fraction. The water content of the product is higher than 20% and preferably ranges from 40% to 70%. The spread is made by fractionating butterfat, in which a high-melting stearin fraction and a low-melting olefin fraction are obtained, and then cooling and working the olefin fraction into a water-in-oil emulsion. While substantial spreadability is achieved, the high water content of the product renders the product substantially different from butter in taste, texture and mouth feel.
U.S. Pat. No. 4,438,149, commonly assigned with the aforenoted patented, teaches a similar product and process, but utilizes the stearin fraction, rather than the olefin fraction, which stearin fraction is combined with a liquid oil, e.g., soybean oil, to form a lowcalorie spread. However, this product, likewise, suffers from the same disadvantage as that of the previously discussed patent.
As can therefore be appreciated from the foregoing, these efforts in the prior art have not been satisfactory for producing a spreadable butter and none of these efforts have met with substantial commercial success. Recently, however, a proposal has been made in the art for producing a composition which has a texture and mouth feel somewhat similar to butter and which composition is based on a different approach from those discussed above. Thus, U.S. Pat. No. 4,511,591 disclosed concentrating a dairy product, such as skim milk, to prepare a dairy protein concentrate. After the concentrate is formed, e.g., by ultrafiltration, butter or concentrated cream is added thereto and homogenized. The fat (from the butter or cream) is disbursed as an oil-in-water emulsion with the protein concentrate forming a natural emulsifier for the oil-in-water emulsion. Emulsification takes place by way of a conventional dairy homogenization step. The product which results is spreadable at refrigeration temperatures. However, the product has a taste dissimilar to butter, and the texture and mouth feel, while somewhat similar to butter, are nonetheless recognizably distinct therefrom. The taste, texture and mouth feel are better described as being similar to cream cheese, as opposed to the taste, texture and mouth feel of butter. The composition also encounters some of the problems encountered by margarine if allowed to warm significantly above refrigeration temperatures.
As can therefore be appreciated, these efforts in the prior art have not been entirely satisfactory. It would therefore be of substantial value to the art to provide a composition which is not only spreadable at refrigeration temperatures but which has all of taste, texture and mouth feel similar to butter, while at the same time will not "oil-out" when the composition reaches temperatures above room temperature.